Question

вычислить:sin18-sin54

Answer 1

sin 54- sin 18 = 2 sin (54-18 /2) *cos (54+18)/2=2 *sin18*cos72=2 sin^2(18)=1-cos36=

 

=1-(1+√5)/4

=(3-√5)/4

=3/4-√5/4